Does System.set write flash each time event the value it is the same?

[ScruffR]

Have you tried that function?
If it does what you want, just use it.

Otherwise you can read flash just as any other memory location.
Have a look at this

Linker error while compiling using CLI

If you only want to read the suffix, you won’t need to unlock the flash, you can just read that address direct. This is a simple sketch that demonstrates that uint8_t *s1 = (uint8_t*)0x80064B8; uint8_t *s2 = (uint8_t*)0x800A4B8; char suffix1[8]; char suffix2[8]; void setup() { Particle.function("setSuffix", setSuffix); } int setSuffix(String arg) { String suffix = arg.substring(0,6); memset(suffix1, 0, sizeof(suffix1)); memcpy(suffix1, s1, sizeof(suffix1)-1); memset(suf…